Lets not forget, you do get to make a whole wonderful person, so any and all of these changes are a small price for that! Some of the changes have direct physiologic benefits to the developing baby, other changes, well, they just seem to be changes.
You make all sorts of new hormones some come directly from the placenta and some from your own production. One of those is a growth hormone related compound so you do burn more fuel per day.
You get less oxygen to the brain.
Your sense of smell gets stronger.
You sweat more.
Your face gets darker pigment, usually in a configuration of a mask.
Your blood volume increases by 50%, but more of this stagnates in your lower legs.
Your lungs get compressed once the uterus grows, so taking a deep breath is harder.
The uterus will grow from an egg size to a watermelon size
Bones and teeth loose just a bit of calcium, and become more brittle because of those.
Your breasts get bigger.
The body produces relaxin and joints get looser, could be great in some yoga poses, for others: watch your balance!
Your center of gravity will shift, actually forward in the bid to lower back.